Hermetic Compressor

ABSTRACT

A hermetic compressor capable of reducing vibration and noise caused by an oil-supply capillary tube during operation thereof. The hermetic compressor comprises a hermetic case, a cylinder block to guide reciprocating movement of a piston, a cylinder head coupled to an end of the cylinder block, a valve unit provided between the cylinder block and the cylinder head to control the flow of a refrigerant, an oil-supply capillary tube having a first end immersed in an oil sump that is defined in a lower region of the hermetic case and a second end communicating with the interior of the cylinder head to supply oil to the valve unit, and a fixing unit integrally formed at the cylinder head to fix the oil-supply capillary tube. With this configuration, the oil-supply capillary tube is securely mounted by the fixing unit during operation of the compressor, resulting in the reduction of vibration and noise.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 2005-35715, filed on Apr. 28, 2005 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hermetic compressor and, more particularly, to a hermetic compressor capable of attenuating vibration of an oil-supply capillary tube, and noise caused by the vibration of the capillary tube.

2. Description of the Related Art

FIG. 1 is a sectional view illustrating the general structure of a conventional hermetic compressor. Referring to FIG. 1, the conventional hermetic compressor is designed such that a crank 4 is connected at one end thereof to a lower end of a rotary shaft 3 and at the other end to a piston 5, thereby allowing the piston 5 to reciprocate in a cylinder 6 as the rotary shaft 3 rotates along with a rotor 2 of a motor. Also, the conventional hermetic compressor is designed to supply oil to cool or lubricate a valve unit mounted in a cylinder head 7. For this, an oil-supply capillary tube 10 is provided in the compressor. One end of the oil-supply capillary tube 10 is immersed in an oil sump 8, which is defined in a lower region of a compressor case 1, and the other end of the oil-supply capillary tube 10 is mounted to communicate with the interior of the cylinder head 7. Thereby, the oil-supply capillary tube 10 serves to introduce oil, received in the oil sump 8, into the cylinder head 7 using a pressure difference between the inside and outside of the cylinder head 7. Here, the pressure difference is caused by the reciprocating movement of the piston 5 in the cylinder 6.

FIG. 2 illustrates the oil-supply capillary tube 10 affixed to the cylinder head 7. As shown in FIG. 2, the oil-supply capillary tube 10 is first sub-assembled to the cylinder head 7, and then, is assembled in the compressor case 1 to complete the final compressor. When being assembled in the compressor case 1, in consideration of a shape restriction in the interior of the compressor case 1, the conventional oil-supply capillary tube 10 is designed to have a bent portion 11 extending from a lower corner region of the cylinder head 7 toward the center of the compressor case 1. With this configuration, the capillary tube 10 is entirely affixed to the cylinder head 7 as one end thereof is located at a fixed position by the bent portion 11 and the other end thereof communicates with the interior of the cylinder head 7. However, the conventional capillary tube 10 has the following problem. After being assembled, if the bent portion 11 is loosened in tension, the capillary tube 10 is separated from the cylinder head 7 due to vibrations caused by the reciprocating movement of the piston 5 and intermittent oil pumping, colliding with an outer wall surface of the cylinder head 7 or an inner wall surface of the compressor case 1. This collision of the capillary tube 10 results in abnormal noise.

SUMMARY OF THE INVENTION

The present invention has been made in order to improve functions of the conventional hermetic compressor as mentioned above, and it is an aspect of the invention to provide a hermetic compressor capable of eliminating vibration of an oil-supply capillary tube and abnormal operation noise.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

In accordance with an aspect, the present invention provides a hermetic compressor comprising: a hermetic case having an oil sump formed in a lower region hereof; a piston; a cylinder block to guide reciprocating movement of the piston therein; a cylinder head coupled to an end of the cylinder block; a valve unit provided between the cylinder block and the cylinder head to control the flow of a refrigerant; an oil-supply capillary tube having a first end immersed in the oil sump and a second end communicating with the interior of the cylinder head to supply oil to the valve unit; and a fixing unit integrally formed at the cylinder head to fix the oil-supply capillary tube.

The fixing unit may be mounted at opposite edges of a seating groove formed at the cylinder head to securely mount the capillary tube to the cylinder head.

The fixing unit may include clamps formed by caulking a pair of protrusions which are located to face each other about the seating groove.

A distance between the pair of protrusions may be 1.4 mm to 2.5 mm.

A distance between facing ends of the pair of clamps may be more than 0.5 mm.

The pair of protrusions is integrally formed with the cylinder head via aluminum die casing.

The fixing unit may include a plurality of guides arranged in a zigzag pattern while interposing a seating groove to secure an outer circumferential surface of the capillary tube.

Each of the guides may have an inner surface that is rounded at an upper end thereof for the smooth insertion of the oil-supply capillary tube.

A distance between extended planes of the inner surfaces of the guides, that may be arranged to face each other by interposing the seating groove, is smaller than an outer diameter of the capillary tube.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more easily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view illustrating the general structure of a conventional hermetic compressor;

FIG. 2 is a partial sectional view illustrating a conventional capillary tube affixed to a cylinder head;

FIG. 3 is a sectional view illustrating the general structure of a hermetic compressor consistent with the present invention;

FIG. 4 is a partially enlarged perspective view illustrating protrusions used to mount an oil-supply capillary tube to a cylinder head consistent with an embodiment of the present invention;

FIGS. 5 a to 5 c are front views illustrating a procedure of affixing the oil-supply capillary tube to the cylinder head as viewed from arrow IV of FIG. 4;

FIG. 6 is a partially enlarged perspective view illustrating guides used to affix the oil-supply capillary tube to the cylinder head consistent with another embodiment of the present invention; and

FIG. 7 is a front view illustrating the oil-supply capillary tube securely mounted to the cylinder head as viewed from arrow V of FIG. 6.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE, NON-LIMITING EMBODIMENTS OF THE INVENTION

Reference will now be made in detail to the illustrative, non-limiting embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The exemplary embodiments are described below to explain the present invention by referring to the drawings.

FIG. 3 is a sectional view illustrating the general structure of a hermetic compressor consistent with the present invention. As shown in FIG. 3, the hermetic compressor consistent with the present invention comprises a hermetic case 30 including upper and lower cases 30 a and 30 b hermetically coupled to each other, a compression unit 40 disposed in the hermetic case 30 and adapted to compress a refrigerant, and a drive unit 50 to generate a drive force required to compress the refrigerant. The case 30 is provided at certain locations with a suction pipe 31 to introduce the exterior refrigerant into the case 30 and a discharge pipe 32 to discharge the refrigerant, compressed in the compression unit 40, to the outside.

The compression unit 40 includes a cylinder block 41 internally defining a compression chamber 41 a for use in the compression of the refrigerant, a piston 42 adapted to linearly reciprocate in the compression chamber 41 a to thereby compress the refrigerant therein, a cylinder head 43 coupled to one end of the cylinder block 41 to seal the compression chamber 41 a, the cylinder head 43 having sectionalized suction and discharge chambers 43 a and 43 b to suction and discharge the refrigerant, and a valve unit 44 provided between the cylinder block 41 and the cylinder head 43 to control introduction of the refrigerant from the suction chamber 43 a into the compression chamber 41 a and discharge of the refrigerant from the compression chamber 41 a into the discharge chamber 43 b.

The drive unit 50, that provides the drive force required to reciprocate the piston 42 in the compression chamber 41 a, includes a stator 51 mounted in the hermetic case 30, and a rotor 52 inwardly spaced apart from the stator 51 to electromagnetically interact with the stator 51. A rotary shaft 53 is press fitted in the center of the rotor 52 to rotate along with the rotor 52. To a lower end of the rotary shaft 53 is coupled an eccentric member 53 a to eccentrically rotate. Also, a connecting rod 54 is rotatably coupled at one end thereof to the eccentric member 53 a and at the other end thereof to a piston 42 to rotate and linearly move along with the piston 42. Thereby, the connecting rod 54 serves to convert eccentric rotation of the eccentric member 53 a into linear movement of the piston 42.

A suction muffler 46 is mounted above the cylinder head 43. The suction muffler 46 has a predetermined inner resonance space. With the suction muffler 46, the refrigerant, introduced into the hermetic case 30 through the suction pipe 31, is attenuated in noise prior to being introduced into the suction chamber 43 a. The suction muffler 46 is connected to the suction chamber 43 a through a guide pipe 47 that extends from a certain location inside of an end of the suction muffler 46 into the suction chamber 43 a.

Meanwhile, a valve unit 44 is provided between the cylinder block 41 and the cylinder head 43 to control introduction of the refrigerant from the suction chamber 43 a into the compression chamber 41 a or discharge of the refrigerant from the compression chamber 41 a into the discharge chamber 23 b. To supply oil for cooling and lubricating the valve unit 44, an oil-supply capillary tube 60 (hereinafter, referred to as capillary tube) is mounted so that one end thereof is immersed in an oil sump 48 provided in a lower region of the compressor case 30, and the other end of the capillary tube 60 communicates with the interior of the cylinder head 43. Thereby, the capillary tube 60 serves to introduce oil, received in the oil sump 48, into the cylinder head 43 using a pressure difference between the inside and outside of the cylinder head 43 caused by reciprocating movement of the piston 42 in the cylinder block 41.

Referring to FIG. 4, the cylinder head 43 is formed at an outer wall surface thereof with an elongated seating groove 62 to mount the capillary tube 60 thereto. The seating groove 62 extends throughout a specific wall surface 43 c of the cylinder head 43 and is configured to receive part of an outer circumferential surface of the capillary tube 60. A pair of protrusions 70 is formed at the center of the wall surface 43 c of the cylinder head 43 to face each other about the seating groove 62.

Referring to FIGS. 5 a to 5 c, a procedure of mounting the capillary tube 60 to the cylinder head 43 is illustrated. Referring first to FIG. 5 a, the pair of protrusions 70 is located at opposite edges 64 of the seating groove 62 defined in the wall surface 43 c of the cylinder head 43. The pair of protrusions 70 has vertical inner surfaces 71 a and 71 b, and downwardly inclined outer surfaces 72 a and 72 b. Preferably, a distance W1 between the inner surfaces 71 a and 71 b of the protrusions 70 is selectable from a relatively wide range of 1.4 mm to 2.5 mm to allow various sizes of capillary tubes having a diameter in a range of 1.4 mm to 2.5 mm to be inserted between the protrusions 70. Also, preferably, the protrusions 70 are integrally formed with the cylinder head 43 via aluminum die casting.

Referring to FIG. 5 b, after the capillary tube 60 is inserted between the protrusions 70, the protrusions 70 are pressed downward using a tool 78, such as a jig. Thereby, as shown in FIG. 5 c, the inner surfaces 71 a and 71 b of the protrusions 70 come into close contact with the outer circumferential surface of the capillary tube 70 to cover it. That is, as the protrusions 70 are calked using the jig 78, they form clamps 75 to prevent the capillary tube 60 from being separated from the seating groove 62. In this case, if excessive force is applied by the jig 78 to thereby cause facing ends of the clamps 75 to collide with each other, it causes reduction in an inner diameter of the capillary tube 60, whereby an inner channel 65 of the capillary tube 60 is often occluded. Therefore, it is preferable that the caulking operation is performed with an appropriate force to keep a distance W2 between the ends of the clamps 75 at a value more than 0.5 mm.

The clamps 75 configured as stated above serve as anchors to secure the capillary tube 60 seated in the seating groove 62.

FIG. 6 illustrates guides to mount the capillary tube to the cylinder head consistent with another embodiment of the present invention.

As shown in FIG. 6, in the present embodiment, three guides 80 are arranged in a zigzag pattern while interposing the seating groove 62 therebetween.

As shown in FIG. 7, inner surfaces 81 a and 81 b of the guides 80 are rounded at upper ends thereof for the smooth insertion of the capillary tube 60. The inner surfaces 81 a and 81 b of the guides 80 are arranged to face each other while interposing the seating groove 62, and a distance W3 between imaginary extended planes of the facing inner surfaces 81 a and 81 b is smaller than an outer diameter D of the capillary tube 60. In this case, preferably, the distance W3 is smaller than the outer diameter D by 0.5 mm. If the distance W3 between the extended planes of the inner surfaces 81 a and 81 b is excessively smaller than the outer diameter D of the capillary tube 60, an excessive constriction force is applied to the capillary tube 60, causing the inner channel 65 of the capillary tube 60 to be occluded.

As stated above, since the distance W3 between the extended planes of the inner surfaces 81 a and 81 b is smaller than the outer diameter D of the capillary tube 60, when the capillary tube 60 is inserted between the guides 80, portions of the capillary tube 60, supported against the guides 80, are forcibly pushed into the seating groove 62. As a result of being forcibly pushed into the seating groove 62 by the three guides 80 which are spaced apart from one another by a predetermined distance, the capillary tube 60 is able to be securely mounted in the seating groove 62 without the risk of unintentional separation. Although the present embodiment employs the three guides 80, it should be understood that two or more guides 80 are sufficient to fix the capillary tube 60.

Now, the operation and effects of the hermetic compressor according to the present invention will be explained.

In the hermetic compressor configured as stated above, if the rotary shaft 53 rotates along with the rotor 52 as the stator 51 electromagnetically interacts with the rotor 52, the piston 42, connected to the eccentric member 53 a via the connecting rod 54, linearly reciprocates in the compression chamber 41 a. Thereby, the exterior refrigerant, which is introduced into the compressor case 30 through the suction pipe 31, is introduced into the suction chamber 43 a of the cylinder head 43 in a noise attenuated state while passing through the suction muffler 46. After that, the refrigerant is again directed from the suction chamber 43 a into the compression chamber 41 a to thereby be compressed therein. The compressed refrigerant is discharged into the discharge chamber 43 b of the cylinder head 43, thereby being finally discharged out of the case 30 through the discharge pipe 32. This procedure is repeatedly progressed, resulting in compression of the refrigerant of the compressor.

In operation of the compressor as stated above, the compressor is subjected to vibration caused by reciprocating movement shock of the piston 42 and intermittent oil supply. However, in the present invention, since the capillary tube 60 is securely mounted to the cylinder head 43 using a fixing unit so as not to generate vibration, there is no noise due to collision between the capillary tube 60 and the inner wall surface of the case 30 or the outer wall surface of the cylinder head 43.

As is apparent from the above description, the present invention provides a hermetic compressor in which an oil-supply capillary tube is securely mounted to a cylinder head, thereby reducing the risk of vibration and noise by the capillary tube during operation of the compressor.

Although the embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A hermetic compressor comprising: a hermetic case having an oil sump formed in a lower region thereof; a piston; a cylinder block to guide reciprocating movement of the piston therein; a cylinder head coupled to an end of the cylinder block; a valve unit provided between the cylinder block and the cylinder head to control the flow of a refrigerant; an oil-supply capillary tube having a first end immersed in the oil sump and a second end communicating with the interior of the cylinder head to supply oil to the valve unit; and a fixing unit integrally formed at the cylinder head to fix the oil-supply capillary tube.
 2. The compressor according to claim 1, wherein the fixing unit is mounted at opposite edges of a seating groove formed at the cylinder head to securely mount the capillary tube to the cylinder head.
 3. The compressor according to claim 2, wherein the fixing unit includes clamps formed by caulking a pair of protrusions which are located to face each other about the seating groove.
 4. The compressor according to claim 3, wherein a distance between the pair of protrusions is 1.4 mm to 2.5 mm.
 5. The compressor according to claim 3, wherein a distance between facing ends of the pair of clamps is more than 0.5 mm.
 6. The compressor according to claim 3, wherein the pair of protrusions is integrally formed with the cylinder head via aluminum die casing.
 7. The compressor according to claim 1, wherein the fixing unit includes a plurality of guides arranged in a zigzag pattern while interposing a seating groove to secure an outer circumferential surface of the capillary tube.
 8. The compressor according to claim 7, wherein each of the guides has an inner surface that is rounded at an upper end thereof for the smooth insertion of the oil-supply capillary tube.
 9. The compressor according to claim 8, wherein a distance between extended planes of the inner surfaces of the guides, that are arranged to face each other by interposing the seating groove, is smaller than an outer diameter of the capillary tube. 